I think their point was the delivery of that garbage over time is subject to entropy, and from first principles probably took more energy consumption than a sustained 84MW over the time period the landfill is a viable source for energy.
I know nothing about landfill engineering here, to be frank, simply being a grease for good online gearing.
A single truck requires more energy to operate in a year than 70k homes do!? I find this extremely difficult to believe.
As far as I can tell, the EIA [1] suggests the average home uses 10,791 kWh a year. A gallon of gasoline contains ~33.7 kWh of energy per the EPA/Wikipedia [2].
This would mean that a single truck would be burning 70,000 * 10,791 / 33.7 = 22,414,540 gallons of gasoline a year or 61,409 gallons a day. Seems like wild bullshit to me.
you should note that a gas engine does not convert all that 33kWh of energy into mechanical energy. a gasoline engine has about a 25% conversion into mechanical energy. https://www.fueleconomy.gov/feg/atv.shtml . diesel might be a bit better than a car but it's city driving by nature.
just heat alone is the largest waste product in a car or truck
A tank of gas is still a tank of gas, regardless of what it gets used for.
Energy in = energy out + waste + energy stored
The truck is barely storing anything on average, so what you've described is energy out and waste, but the calculations to compare the truck to the landfill was done on Energy in - the amount of gas that it needs to be filled with.
For the same total job, you could raise or lower how quickly the truck goes through a tank of gas, but that variance has already been averaged out
According to [1] an electric garbage truck traveling 15,000 miles a year uses about 38,960 kWh. An 84 MW power plant produces 84,000 kWh every hour, or enough to power more than two trucks for an entire year. Even if we assume that the diesel equivalent uses a hundred times as much it's still a tiny fraction of what the plant in TFA produces.
Couple issues with that comparison: 15k seemed low given I drive ~10k a year and I don't work a job that uses my car, so I checked refuse trucks drive on average more like 25k miles per year and there are many servicing a single dump. Also most garbage trucks are still diesel so you've got to 5-10x that power usage number and there's all the vehicles used to compact and move the trash once it reaches the landfill which are also (currently) pretty exclusively diesel powered (think bulldozers and soil compactors with some excavators thrown in).
A 500 hp semi truck engine running at peak power is like 350 kw, so 84 megawatts (84,000 kw) is more than 200 of those engines at full throttle at all times.
You’re gonna have a tough time finding any evidence that running a landfill requires 84MW of electricity.